1. Field of the Invention
The present invention generally relates to a hybrid vehicle control apparatus for a hybrid vehicle equipped with an engine and an electric motor as power sources. More specifically, the present invention relates to a hybrid vehicle control apparatus in which an occurrence of vibration and noise resulting from resonance can be suppressed when an engine of a hybrid vehicle is stopped while a holding element arranged between the engine and an electric motor of the hybrid vehicle is in an engaged state.
2. Background Information
One example of a conventional hybrid vehicle control apparatus for a hybrid vehicle is disclosed in Japanese Laid-Open Patent Publication No. 11-82261 (hereinafter referred to as “the conventional control apparatus”). In the conventional control apparatus, a holding element is arranged between the internal combustion engine and the electric motor, and serves to selectively connect and disconnect the engine and the motor to and from each other. A transmission is arranged between the electric motor and a drive wheel. As drive modes, the conventional control apparatus has an electric (EV) drive mode in which the vehicle uses only the electric motor as a power source and an engine drive mode in which the vehicle uses at least the internal combustion engine as a power source. The apparatus improves the fuel efficiency of the vehicle by switching between the two drive modes in accordance with a driving condition.
In the conventional control apparatus, when a request to stop the engine is issued (e.g., if a driver turns an ignition switch off) while the holding element is engaged and the engine is running, it is conceivable that the engine will be stopped with the holding element remaining in a fully engaged state instead of being stopped after the holding element has been temporarily released.